The Incoming Solar Radiation

Abstract We found that a positive sea surface temperature (SST)–precipitation relationship in the western tropical Pacific (WTP) during boreal spring, in which higher SSTs are associated with higher precipitation, episodically weakens from the late 1990s to the early 2010s. During 1980–98, warm SSTs induce positive precipitation and low pressure in the WTP. The associated enhanced convection dampens the initial warm SSTs by reflecting incoming solar radiation. The reduced incoming solar radiation into the ocean leads to a SST cooling tendency. In contrast, the associated southwesterly wind anomalies reduce oceanic mixing by decreasing the mean wind, contributing to an SST warming tendency, though relatively small. Therefore, the cloud–radiation effect is a dominant process of the negative SST tendency. By contrast, during 1999–2014, although an SST cooling tendency is similarly induced by warm SST anomalies, the cooling tendency is enhanced by anomalous ocean advection, as a result of enhanced easterly wind anomalies in the southern part of the WTP. This results in a weakening of a positive relationship of the SST and precipitation during 1999–2014. As such, the associated anomalous convective heating in the WTP during 1999–2014 is weak, changing the atmospheric teleconnection patterns in the midlatitude and surface air temperature anomalies in western North America and northeastern Eurasia.

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A Simple Modeling Tool and Exercises for Incoming Solar Radiation Demonstrations

Journal of Geoscience Education ◽

10.5408/1.3651449 ◽

2011 ◽

Vol 59 (4) ◽

pp. 219-228 ◽

Cited By ~ 1

Author(s):

Scott Werts ◽

Linda Hinnov

Keyword(s):

Solar Radiation ◽

Modeling Tool ◽

Incoming Solar Radiation ◽

Simple Modeling

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Aerosol-radiation feedback deteriorates the wintertime haze in North China Plain

10.5194/acp-2018-1288 ◽

2019 ◽

Author(s):

Jiarui Wu ◽

Naifang Bei ◽

Bo Hu ◽

Suixin Liu ◽

Meng Zhou ◽

...

Keyword(s):

Solar Radiation ◽

Air Pollutants ◽

North China Plain ◽

North China ◽

Radiative Properties ◽

Surface Cooling ◽

Near Surface ◽

Incoming Solar Radiation ◽

Haze Pollution ◽

Pm2.5 Concentration

Abstract. Atmospheric aerosols or fine particulate matters (PM2.5) scatter or absorb a fraction of the incoming solar radiation to cool or warm the atmosphere, decreasing surface temperature and altering atmospheric stability to further affect the dispersion of air pollutants in the planetary boundary layer (PBL). In the present study, simulations during a persistent and heavy haze pollution episode from 05 December 2015 to 04 January 2016 in the North China Plain (NCP) were performed using the WRF-CHEM model to comprehensively quantify contributions of the aerosol shortwave radiative feedback (ARF) to near-surface PM2.5 mass concentrations. The WRF-CHEM model generally performs well in simulating the temporal variations and spatial distributions of air pollutants concentrations compared to observations at ambient monitoring sites in NCP, and the simulated diurnal variations of aerosol species are also consistent with the measurements in Beijing. Additionally, the model simulates well the aerosol radiative properties, the downward shortwave flux, and the PBL height against observations in NCP during the episode. During the episode, the ARF deteriorates the haze pollution, increasing the near-surface PM2.5 concentration in NCP by 10.2 μg m−3 or with a contribution of 7.8 %. Sensitivity studies have revealed that high loadings of PM2.5 during the episode attenuate the incoming solar radiation down to the surface, cooling the temperature of the low-level atmosphere to suppress development of PBL and decrease the surface wind speed, further enhancing the relative humidity and hindering the PM2.5 dispersion and consequently exacerbating the haze pollution in NCP. The ensemble analysis indicates that when the near-surface PM2.5 mass concentration increases from around 50 to several hundred μg m−3, the ARF contributes to the near-surface PM2.5 by more than 20 % during daytime in NCP, substantially aggravating the heavy haze formation. However, when the near-surface PM2.5 concentration is less than around 50 μg m−3, the ARF generally reduces the near-surface PM2.5 concentration due to the consequent perturbation of atmospheric dynamic fields.

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Distinguishing ice-rich and ice-poor permafrost to map ground temperatures and ground ice occurrence in the Swiss Alps

The Cryosphere ◽

10.5194/tc-13-1925-2019 ◽

2019 ◽

Vol 13 (7) ◽

pp. 1925-1941 ◽

Cited By ~ 5

Author(s):

Robert Kenner ◽

Jeannette Noetzli ◽

Martin Hoelzle ◽

Hugo Raetzo ◽

Marcia Phillips

Keyword(s):

Solar Radiation ◽

Thermal Characteristics ◽

Mapping Method ◽

Swiss Alps ◽

Ground Ice ◽

Climate Conditions ◽

Distribution Maps ◽

Ground Temperatures ◽

Incoming Solar Radiation ◽

Gravitational Processes

Abstract. Mountain permafrost is invisible, and mapping it is still a challenge. Available permafrost distribution maps often overestimate the permafrost extent and include large permafrost-free areas in their permafrost zonation. In addition, the representation of the lower belt of permafrost consisting of ice-rich features such as rock glaciers or ice-rich talus slopes can be challenging. These problems are caused by considerable differences in genesis and thermal characteristics between ice-poor permafrost, occurring for example in rock walls, and ice-rich permafrost. While ice-poor permafrost shows a strong correlation of ground temperature with elevation and potential incoming solar radiation, ice-rich ground does not show such a correlation. Instead, the distribution of ice-rich ground is controlled by gravitational processes such as the relocation of ground ice by permafrost creep or by ground ice genesis from avalanche deposits or glacierets covered with talus. We therefore developed a mapping method which distinguishes between ice-poor and ice-rich permafrost and tested it for the entire Swiss Alps. For ice-poor ground we found a linear regression formula based on elevation and potential incoming solar radiation which predicts borehole ground temperatures at multiple depths with an accuracy higher than 0.6 ∘C. The zone of ice-rich permafrost was defined by modelling the deposition zones of alpine mass wasting processes. This dual approach allows the cartographic representation of permafrost-free belts, which are bounded above and below by permafrost. This enables a high quality of permafrost modelling, as is shown by the validation of our map. The dominating influence of the two rather simple connected factors, elevation (as a proxy for mean annual air temperature) and solar radiation, on the distribution of ice-poor permafrost is significant for permafrost modelling in different climate conditions and regions. Indicating temperatures of ice-poor permafrost and distinguishing between ice-poor and ice-rich permafrost on a national permafrost map provides new information for users.

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